Using the CRISPR/Cas9 technology, the Nestin locus in ES cells were targeted to insert loxP, rox, d4GFP, SV40 poly-A, rox, stop cassette, loxP, Flpo, and bGH poly-A at the start codon of the mouse Nes gene. d4GFP is flanked by rox sites and can be removed by crossing to a Dre-deleter mouse. Cre excises the d4GFP and stop cassette, allowing Flpo expression when Nestin is expressed.